Field of the Invention
The present invention relates to a catalyst installation structure of an outboard motor, in which a catalytic converter for purifying or cleaning up an exhaust gas (or merely exhaust) discharged from a four-stroke-cycle engine mounted in an outboard is installed to an exhaust passage.
Rerated Art
Prior art of an outboard motor of conventional art has provided an exhaust device, in which an outboard motor is provided with an exhaust passage (or exhaust gas passage) for guiding an exhaust (gas) outside the engine, and a catalyst for cleaning up the exhaust gas is disposed inside the exhaust passage such as disclosed in Japanese Patent Laid-open No. 2010-242744 and No. 2013-124594 (Patent Documents 1 and 2).
In an outboard motor particularly disclosed in the Patent Document 1, however, a catalyst is disposed in a manner supported in a vertical direction between a catalyst housing portion and an exhaust gas guide. Because of such arrangement, in an event when a relative change in dimension in an axial direction is caused between the catalyst, the catalyst housing portion and the exhaust gas guide, the catalyst is thermally excessively expanded, and in an adverse case, the catalyst may be destroyed.